Two semi-rigid parts that are bonded together may have a risk of disbonding if the two parts each experience different levels of strain at a same point along the bond between the parts. For example, a skin of a wing structure of an aircraft may have a number of structural members, or “stringers,” joined to one surface in order to provide shape, strength, and rigidity to the skin. The strains experienced by the skin and the stringer may be the same at most points along the wing structure. However, at a point where the stringer terminates, the skin and the stringer may experience differing levels of strain when the wing structure is loaded, such as during flight. If the stringer is joined to the skin in a traditional method, such using rivets or bolts, the differing strains in the stringer and skin may be tolerated by the joint, since the members are allowed to “fret” or move relative to each other without the joint failing.
If the stringer is bonded to the skin using a rigid material, however, such as an adhesive that is hard or brittle when it cures, then the difference in strains between these two members may cause the adhesive to fail and the stringer to disbond from the skin. Alternatively, the adhesive may hold, but the differing strains may cause a delamination of the layers of a composite skin and/or stringer. Such a disbond or delamination may cause fuel leakage from the wing tanks, excessive aircraft noise during flight, weakening of the wing structure, and the like. Different solutions have been implemented to reduce the risk of disbonding between the stringer and the skin, such as softening the stringer, adding additional bolts or fasteners to the joint, tapering or feathering the stringer at the point of differing strains, and the like. However, none of these solutions sufficiently reduces the risk of disbond between the members when the wing structure is under load.
It is with respect to these and other considerations that the disclosure made herein is presented.